Antisense technology is an effective means for reducing the expression of one or more specific gene products and can therefore prove to be uniquely useful in a number of therapeutic, diagnostic, and research applications. Chemically modified nucleosides are routinely used for incorporation into antisense sequences to enhance one or more properties such as for example affinity and nuclease resistance. One such group of chemically modified nucleosides includes tetrahydropyran nucleoside analogs wherein the furanose ring is replaced with a tetrahydropyran ring.
The synthesis of tetrahydropyran nucleoside analogs has been reported in the literature, see for example: Verheggen et al., J. Med. Chem., 1995, 38, 826-835; Altmann et al., Chimia, 1996, 50, 168-176; Herdewijn et al., Bioorganic & Medicinal Chemistry Letters, 1996, 6 (13), 1457-1460; Verheggen et al., Nucleosides & Nucleotides, 1996, 15(1-3), 325-335; Ostrowski et al., J. Med. Chem., 1998, 41, 4343-4353; Allart et al., Tetrahedron., 1999, 55, 6527-6546; Wouters et al., Bioorganic & Medicinal Chemistry Letters, 1999, 9, 1563-1566; Brown, et al., Drug Development Res., 2000, 49, 253-259; published PCT application: WO 93/25565; WO 02/18406; and WO 05/049582; U.S. Pat. Nos. 5,314,893; 5,607,922; and 6,455,507.
Various tetrahydropyran nucleoside analogs have been described as monomers and have also been incorporated into oligomeric compounds (see for example: Published PCT application, WO 93/25565, published Dec. 23, 1993; Augustyns et al. Nucleic Acids Res., 1993, 21(20), 4670-4676; Verheggen et al., J. Med. Chem., 1993, 36, 2033-2040; Van Aerschol et al., Angew. Chem. Int. Ed. Engl., 1995, 34(12), 1338-1339; Anderson et al., Tetrahedron Letters, 1996, 37(45), 8147-8150; Herdewijn et al., Liebigs Ann., 1996, 1337-1348; De Bouvere et al., Liebigs Ann./Recueil, 1997, 1453-1461; 1513-1520; Hendrix et al., Chem. Eur. J., 1997, 3(1), 110-120; Hendrix et al., Chem. Eur. J., 1997, 3(9), 1513-1520; Hossain et al, J. Org. Chem., 1998, 63, 1574-1582; Allart et al., Chem. Eur. J., 1999, 5(8), 2424-2431; Boudou et al., Nucleic Acids Res., 1999, 27(6), 1450-1456; Kozlov et al., J. Am. Chem. Soc., 1999, 121, 1108-1109; Kozlov et al., J. Am. Chem. Soc., 1999, 121, 2653-2656; Kozlov et al., J. Am. Chem. Soc., 1999, 121, 5856-5859; Pochet et al., Nucleosides & Nucleotides, 1999, 18 (4&5), 1015-1017; Vastmans et al., Collection Symposium Series, 1999, 2, 156-160; Froeyen et al., Helvetica Chimica Acta, 2000, 83, 2153-2182; Kozlov et al., Chem. Eur. J., 2000, 6(1), 151-155; Atkins et al., Parmazie, 2000, 55(8), 615-617; Lescrinier et al., Chemistry & Biology, 2000, 7, 719-731; Lescrinier et al., Helvetica Chimica Acta, 2000, 83, 1291-1310; Wang et al., J. Am. Chem., 2000, 122, 8595-8602; US Patent Application US 2004/0033967; Published US Patent Application US 2008/0038745; Published and Issued U.S. Pat. No. 7,276,592). DNA analogs have also been reviewed in an article (see: Leumann, J. C, Bioorganic & Medicinal Chemistry, 2002, 10, 841-854) which included a general discussion of tetrahydropyran nucleoside analogs (under the name: hexitol nucleic acid family).
Oligomeric compounds having phosphodiester linked 3′-H tetrahydropyran nucleoside analogs (also referred to in the art as HNA—hexitol nucleic acids or 1,5-anhydrohexitol nucleic acids) have been prepared for evaluation in cell assays. The different motifs that have been evaluated are fully modified wherein each monomer is a phosphodiester linked 3′-H tetrahydropyran nucleoside analog and gapped wherein each monomer in the 5′ and 3′ external regions of the oligomeric compound are each phosphodiester linked 3′-H tetrahydropyran nucleoside analogs and each monomer in the internal region is a phosphorothioate linked deoxyribonucleoside (see: Kang et al., Nucleic Acids Research, 2004, 32(14), 4411-4419; Vandermeeren et 42000, 55, 655-663; Flores et al., Parasitol Res., 1999, 85, 864-866; and Hendrix et al., Chem. Eur. J. 1997, 3(9), 1513-1520).
Oligomeric compounds having phosphodiester linked 3′-OH tetrahydropyran nucleoside analogs (also referred to in the art as ANA or D-altritol nucleic acids) have been prepared and evaluated both structurally and in vitro (Allart et al., Chem. Eur. J., 1999, 5(8), 2424-2431).
Chemically modified siRNA's having incorporated hexitol nucleotides have been prepared and tested for silencing capacity (see: Published PCT application, WO 06/047842, published May 11, 2006.
Consequently, there remains a long-felt need for agents that specifically regulate gene expression via antisense mechanisms. Disclosed herein are tetrahydropyran nucleoside analogs that are useful in the preparation of antisense compounds for modulating gene expression pathways, including those relying on mechanisms of action such as RNaseH, RNAi and dsRNA enzymes, as well as other antisense mechanisms based on target degradation or target occupancy. One having skill in the art, once armed with this disclosure will be able, without undue experimentation, to identify, prepare and exploit antisense compounds for these uses.